Originally Posted by
irishguy28
Given that the OP probably won't have a lot of time to faff about, I would recommend just buying the ticket, travelling to Gatwick, and submitting the ticket with a claim for reimbursement after the trip is completed.
I would tend to agree, but it does sound like the OP may have quite a comfortable connection so it might be worth taking a few minutes to ascertain the lie of the land.
Finding someone to hand over a voucher may be, as you say, an entirely different matter though - I've no idea how difficult this would be, as I usually terminate at LHR/LCY or have a planned airport change, so transfer costs are then my responsibility anyway.